The all-electric vehicle, with its gentle curves, lightweight composite body and battery technology that just won’t quit, certainly gave D.C. quite a show last week. It stopped by several locations around town, so folks could ask questions and get a feel for what might serve as the city’s next Circulator.

Those familiar red buses with the $1 fare are circa 2003, which means they’re nearing the end of their lifespan, explains Will Handsfield, transportation director for the Georgetown Business Improvement District. The BID and other stakeholders are trying to determine the best choice to replace the fleet, he says, so they’re organizing one-day showcases this year for the front-runners.

First up, Proterra from South Carolina. That’s how Hill ended up standing in front of the U.S. Department of Transportation headquarters, giving a sales pitch for his product. It’s the only battery-run bus on the market that can operate continuously for 24 hours, he boasted. The magic is in its charging mechanism: At a spot along its route, the vehicle can sit under a lamppost-height power station while unloading and loading passengers. In five minutes, it’ll have an extra hour of juice. (Fully charged, it can go for three hours, he added, so missing a single refueling won’t lead to disaster.)

Nearly 50 Proterra buses have already hit the streets in other cities across the country, including Pomona, Calif., Reno, Nev., and Worcester, Mass. In all of the markets, Hill said, the passengers’ response has been the same: “Once they ride this bus, they love it.”

So I figured I needed to go for a spin.

When the bus was slated to head to its next stop on its promo tour, I got on board. Then I heard a low rumble, which threw me. A main selling point of electric vehicles is that they can sneak silently through neighborhoods, so what gives?

Turns out, that was just the air conditioning flipping on. Otherwise, the bus was as quiet as promised, and Hill pointed out a few fun features: a bright rear window, doors wide enough for two people to exit simultaneously, a dashboard meter that lets the driver know how much power is left.

But the best part, Hill said, is the cost. A Proterra bus runs about $1 million, which is twice the price of a typical diesel bus, but once you factor in fuel savings and reduced maintenance, the bottom line is about the same.

“For green technology, you can hug all of the trees you want, but if it’s too expensive, people won’t buy it,” Hill said.

The question is: Will D.C.? Option number two — BYD’s Chinese-designed, American-built electric model — is expected to roll into town in August.